Moving plates form what tyes of boundaries?

A physics book is thrown horizontally at a velocity of 5.0 m/s from the top of a cliff 78.4 m high. How long does the book take

xenn [34]

The book's vertical position in the air is

$y=78.4\,\mathrm m-\dfrac12gt^2$

where $g=9.80\,\frac{\mathrm m}{\mathrm s}$ . It reaches the ground when $y=0$ , at a time $t$ such that

$0=78.4\,\mathrm m-\dfrac12gt^2\implies t=4.00\,\mathrm s$

So it takes the book 4 seconds to reach the bottom. The given initial velocity is irrelevant since it only has a horizontal component; vertically, the book is starting from rest.

3 0

3 years ago

Natasha weighs 530N. what is her kinetic energy as she swimsat

WITCHER [35]

<u>Answer:</u> The kinetic energy of Natasha as she swim is 38.88 J

<u>Explanation:</u>

Force is defined as the mass multiplied by the acceleration of the object.

Mathematically,

$F=m\times a$

where,

F = weight of Natasha = 530 N

m = mass of Natasha = ?

a = acceleration due to gravity = $9.8m/s^2$

Putting values in above equation, we get:

$530kg.m/s^2=m\times 9.8m/s^2\\\\m=\frac{530}{9.8}=54kg$

Speed is defined as the rate at which an object moves with respect to time. To calculate the speed, we use the equation:

$s=\frac{d}{t}$

where,

d = distance traveled = 72 m

t = time taken by Natasha = 1.0 min = 60 sec (Conversion factor: 1 min = 60 s)

Putting values in above equation, we get:

$s=\frac{72}{60}=1.2m/s$

Kinetic energy is defined as the energy which is possessed due to its motion. It is also defined as the half of the product of mass of the object and square of the velocity of the object.

Mathematically,

$E_K=\frac{1}{2}mv^2$

where,

$E_K$ = kinetic energy of Natasha

m = mass of the Natasha = 54 kg

v = velocity of Natasha = 1.2 m/s

Putting values in above equation, we get:

$E_K=\frac{1}{2}\times 54\times (1.2)^2\\\\E_K=38.88J$

Hence, the kinetic energy of Natasha as she swim is 38.88 J

3 0

3 years ago

The rubber and plastic used in protective clothing do not allow the flow of electric charge

erica [24]

Answer:

True

Explanation:

Insulators are the material that does not allow electricity to pass easily through them. The reason behind using an insulator as a protective layer on an electrical wire or appliances is that they show good resistance to electricity. That prevents us from getting an electrical shock. And rubber and plastics are good examples of the insulator.

Hence our statement is true.

6 0

3 years ago

A device has a least count of 0.01m if it measures a length less than 100m the minimum and maximum number of significant figure

Klio2033 [76]

Answer:

C) 1 and 4

Explanation:

Least count is .01 m . If one measures any number between 100 and 99 , it will be like 99.25 or 99.37 m . So number of significant figure will be 4 ( maximum )

The least one can measure is .01 so least number of significant figure possible is 1 .

5 0

2 years ago

Only 25% of the intensity of a polarized light wave passes through a polarizing filter. What is the angle between the electric f

Firdavs [7]

Answer: Only 25% of the intensity of a polarized light wave passes through a polarizing filter. Then the angle between the electric field and the axis of the filter will be 60 degrees.

Explanation: To find the answer of the problem given, we have to know about the Malu's law of polarization.

<h3>What is Malu's law of polarization?</h3>

This law states that, when a beam of completely polarized light is passed through an analyzer, then then intensity I of the transmitted light varies directly as the square of the angle $\alpha$ between the transmission direction of the polarizer and the analyzer.
The expression for this law will be,

$I=I_0cos\alpha$

Where, I₀ is the maximum intensity of the transmitted light through the polarizer.

<h3>How to solve the problem?</h3>

From the question, it is clear that, the 25% of the intensity of a polarized light wave passes through the filter.

$\frac{I}{I_0} =0.25\\$

Thus, the angle between electric field and the axis of the filter is,

$cos^2\alpha =0.25\\cos\alpha =\sqrt{0.25} =0.5\\\alpha =cos^-1(0.5)=60 degrees$

Thus, we can conclude that, the angle between the electric field and the axis of the filter will be 60 degrees.

Learn more about the Malus law of polarization here:

brainly.com/question/28020002

#SPJ4

4 0

2 years ago